This invention relates in general to power take-offs for selectively providing rotational energy from a source of rotational energy to a driven accessory. In particular, this invention relates to an improved structure for such a power take-off that significantly reduces the amount of undesirable noise that is transmitted through the power take-off during operation.
A power take-off is a well known mechanical device that is often used in conjunction with a source of rotational energy, such as a vehicle engine or transmission, to provide rotational energy to a driven accessory, such as a hydraulic pump that is supported on the vehicle. For example, power take-offs are commonly used on industrial and agricultural vehicles to provide rotational energy to hydraulic pumps that, in turn, are used to operate hydraulically driven accessories such as plows, trash compactors, lifting mechanisms, winches, and the like. The power take-off provides a simple, inexpensive, and convenient means for supplying energy from the source of rotational energy to the hydraulic pump that, in turn, provides relatively high pressure fluid to operate the driven accessory.
A typical power take-off includes an input mechanism and an output mechanism. The input mechanism of the power take-off is adapted to be connected to the source of rotational energy so as to be rotatably driven whenever the source of rotational energy is operated. The output mechanism of the power take-off is adapted to be connected to the rotatably driven accessory. In some instances, the input mechanism of the power take-off is directly connected to the output mechanism such that the driven accessory is rotatably driven whenever the source of rotational energy is operated. In other instances, a clutch assembly is provided between the input mechanism and the output mechanism such that the driven accessory is selectively rotatably driven only when the source of rotational energy is operated and the clutch assembly is engaged.
When a typical power take-off is operated, however, it often transmits an undesirable amount of noise therethrough from the source of rotational energy to the ambient environment. Such noise usually results, at least in part, from torsional vibrations that are generated from the vehicle engine and transmitted through the transmission to the power take-off. It has been found that such torsional vibrations can cause loosely meshing gears contained within the power take-off to rattle against one another as they are rotatably driven during use. Although the generation of such noise does not usually adversely affect the operation of the power take-off, it can be quite bothersome to persons that are located in the ambient environment. Thus, it would be desirable to provide an improved structure for a power take-off that significantly reduces the amount of this undesirable noise that is transmitted through the power take-off.